1. Field of the Invention
The present disclosure relates generally to the field of monitoring water in water lines, and in particular, to monitoring residential water supplies to measure dissolved solids.
2. Description of the Related Art
Availability of water is perhaps the most essential factor in determining where humans can live, raise food, and develop industry. Considerable resources are spent finding, moving, storing, and purifying water for human consumption. At the same time, water contamination is a large and growing problem. Point sources, such as sewage systems, feed lots, and industrial waste discharge, combines with non-point sources, such as cropland runoff from fertilizers and insecticides, highway runoff of oil and other automotive products, and atmospheric pollution captured by rain water, to raise the level of contaminants in the water that we rely on. This is in addition to natural mineral contaminants that are collected by water in rivers and aquifers.
Most water contaminants are carried as dissolved solids in the water. Generally, water purity is classified in relation to the total dissolved solids (TDS) in the water, and is measured in parts-per-million (ppm), by weight. In any given water sample there will be a combination of many contaminants, natural and man-made, that make up the TDS value of the sample. While concentrations of particular contaminants can be harmful at relatively low levels, as a rule, potability is classified in accordance with the TDS value of a water sample. The U.S. Environmental Protection Agency guidelines establish 500 ppm as a maximum acceptable level of TDS for drinking (potable) water. Levels above around 300 ppm usually affect the appearance or taste of water. Average tap water in the U.S. ranges between 140 and 400 ppm, with hard water above around 170 ppm. Commercial carbon/particulate filters can produce water in a range of around 50-150 ppm, while water below 50 ppm can be produced by reverse-osmosis filters, distillation, de-ionization, micro-filtration, etc. Extremely pure water below around 25-30 ppm is corrosive to some materials.
Notwithstanding the growing problems and concerns surrounding the question of water purity and availability, most of the water provided in the U.S. for domestic use is well within the standards established, and is safe for use. However, despite this fact, and the fact that most municipal treatment facilities operate to standards that far exceed the minimum standards set federally, most consumers have some level of concern for the quality of their own tap water. These concerns are fueled by news of intentional and accidental spills infiltrating the water supply, and by the aggressive advertising of the growing bottled and filtered water industry. As a result, many people routinely filter their tap water or buy bottled water.
The cost of filtering tap water is generally between three and twenty cents per gallon, while bottled water usually costs more than a $1 per gallon, and can be as high as $4 per gallon. Yet many people are unwilling to trust that their tap water will always be safe, and prefer, instead, to pay a premium for a real or perceived reliable source of clean water.